The Partial Discharge Monitoring Systemfor Transformer And GIS

With the smart grid construction,the safe operation of transformer and GIS is directly related to the security of power system.Insulation monitoring can assess the degree of insulation damage to equipment;it can help the staff to determine whether the device can continue to run.Therefore,partial discharge monitoring can reflect the internal insulation of electrical equipment.Partial discharge monitoring has a very important influence on the stability of power systems.This paper studies the partial discharge problem in transformers and GIS.Using sensor technology,analog electronics technique,digital signal processing,artificial intelligence algorithm and virtual instrument technology to design a set of partial discharge monitoring system for the transformer and the GIS.Thepartial discharge monitoring system uses ultrasonic and UHF to detect the partial discharge.If the partial discharge exists in the device,we can use the ultrasonic to know where the point it is.The system uses the Labview as the tools to realize the signals collection,processing and recognition,positioning,and data storage,etc.The digital signal processing unit mainly completes the denoising of partial discharge signals.The surrounding noise will have an impact on partial discharge detection when the system works.The best way to solve the problem is denoising.This paper uses the EMD algorithm and wavelet algorithm to reduce the influence of the noise.The BP neural network is used to establish the recognition model of the partial discharges which can realize the intelligent identification and classification of the partial discharge types.The system can judge the partial discharge type by contrast ultrasonic signal and UHF signal.According to the experimental simulation,the simulation result is very beautiful.We can know the location of the partial discharge points by using ultrasonic signal.The time is different which the signal arrives different sensors.We can use generalizedcross-correlation to calculate time delay between each sensor by analyzingof partial discharge signals in transformer and GIS and use the relevant algorithm tocalculate the partial discharge points.Data acquisition card is used to establish connection between slave computer and master computer.Firstly,the signal is processes by the partial discharge monitoring system,then the system determine whether there is a partial discharge point in the device.Finally,the system will give out the type of partial discharge and the location of the partial discharge points.